The first Memorial Day — then called Decoration Day — was celebrated May 30, 1868, three years after the end of the Civil War to honor the Union dead. Compared to a national population of 31.4 million in 1860, the Civil War dead, both Union and Confederate, are now roughly estimated at 750,000 and possibly more.
After World War I, the holiday commemorated all U.S. war dead. In 1971, Memorial Day became an official national holiday. “Historical Statistics of the United States (Millennial Edition)” lists war dead by conflicts as follows: the Revolutionary War, 4,435; the War of 1812, 2,260; the Mexican War, 13,283; the Spanish-American War, 2,446; World War I, 116,516; World War II, 405,399; the Korean War, 36,576; the Vietnam War, 58,200; the Persian Gulf War, 382. In addition, the Pentagon reports 6,809 deaths in the wars in Iraq and Afghanistan and related combat zones as of May 22